The art of the present invention relates to sheet material or sheet metal seam or joint forming equipment in general and more specifically to a pass through inline seam rollformer capable of forming male and/or female lock seams in a single pass without an unnecessary lateral or horizontal movement of the sheet material, all while maintaining a minimum of floor space. The process of passing sheet material through consecutive sets of rollers, dies, or tooling with each performing an incremental part of a bend on the material to form a desired cross-sectional profile is known within the pertinent arts as “rollforming”.
Sheet metal air ducts are manufactured in a plurality of styles and design configurations including but not limited to round, oval, square, and rectangular. Within the United States, ductwork and heating, ventilating, and air conditioning (HVAC) products are governed by standards set and recognized by the Sheet Metal and Air Conditioning Contractors National Association (SMACNA). Formation of said ducts and sheet metal fittings utilize a wide variety of locking, joining, and flanging methods which are produced by shearing, notching, and folding sheets of sheet metal or other sheet material. Often said sheets are formed and/or fed from a coil of sheet metal material.
Smaller heating and air conditioning contractors often utilize simple shears, brakes and lock seam rollformers to manufacture ductwork and associated fittings from pre-cut sheet metal. This prior art method is often time consuming and costly. As production volume and demand increase, contractors seek equipment and items which reduce labor cost and increase production capabilities, often in the form of automatic or semi-automatic coil fed duct forming equipment. Some ductwork manufacturers produce duct primarily for the residential (i.e. new homes) and light commercial (i.e. stores and offices) markets while other duct manufacturers fabricate for the light to heavy industrial and major commercial markets. Each contractor or manufacturer has special needs for improvement of the production process in the early stages of duct fabrication.
For square or rectangular ductwork, a fully automated duct forming system (See FIG. 1) beads, notches, and shears sheet metal stock to size, (See FIG. 2) rollforms each seam that joins the square or rectangular ducts together, then rollforms the end flanges that join each completed duct section together when they are assembled and hung. After all of the seams and flanges are formed, the duct sections are often automatically glued, insulated, and/or pinned. Thereafter, the insulated or non-insulated flat formed sections are folded to produce square and/or rectangular ductwork via two (2) piece or one (1) piece full wrapper duct sections. (See FIGS. 3 & 4)
A plurality of fully automated duct forming systems are fed from a coil of sheet metal with decoilers, straighteners, beaders, notchers, and shears performing operations on the sheet metal as it is fed through the automated duct system. (See FIG. 1) Sheets having notches, beads, and other attributes are formed (i.e. cut from the roll) with the automated duct system whereby “L” shaped or full wrapper square or rectangular ductwork is formed therefrom. Typically the ductwork seam is joined together by forming (i.e. rollforming) either a “pittsburg” or “snap lock” lock seam across the leading and trailing ends of the pre-cut and notched sheet metal. (See FIGS. 5 & 6) That is, a first end of the sheet metal is typically formed with a male “pittsburg” or “snap lock” and a second end is formed with the female “pittsburg” or “snap lock”.
A fully automated duct forming system or line is highly desirable in order to minimize labor and fabrication time. Unfortunately, prior art fully automated duct forming systems have been prohibitively costly and utilize substantial floor space, all to the detriment of smaller or mid-size ductwork fabricators. Smaller manufacturers may minimize the capital costs of a fully automated duct forming system via utilization of a semi-automatic duct forming system yet often require the smallest footprint possible as their facilities may be limited in size. Even if a smaller manufacturer utilizes a semi-automatic duct forming system, the ability to integrate the semi-automatic system with or into a fully automated system is highly desired in order to meet future expansion and growth.
Additional capabilities for semi-automatic systems which improve throughput and reduce costs include equipment to seam or rollform the sides together, equipment to flange or rollform the ends, and equipment to fold the duct line into a two piece (i.e. “L” shape) or one piece four (4) sided duct (i.e. full wrapper). One of the most popular options for the semi-automatic duct forming line is the fold and shear equipment which folds a notched blank into an “L” or full wrapper shape prior to cutting to length. Unfortunately, the prior art fold and shear equipment requires rollforming of the seamed edge (i.e. the female “pittsburgh” or “snap lock”) after the duct has been formed. This is often difficult and time consuming, especially when the duct is formed into a four sided full wrapper form.
With special modifications, some fold and shear equipment can form the male “pittsburgh” and male “snap lock” lock seams. Unfortunately, this often requires a 90 degree transfer of the wrapper duct into a rollformer or removal from the production line with the seamed edge produced on a manual feed rollformer. That is, the pre-notched sheet or pre-formed duct must be shuttled 90 degrees offline to rollform the “pittsburg” or “snap lock” seams on one or both ends of the duct. For the prior art, this 90 degree transfer is required on both fully automatic and semi-automatic fold and shear duct lines. (See FIGS. 1 & 7)
The present art represents a an inline pass through seam rollformer which travels across (i.e. laterally) the sheet material or metal rather than the sheet material passing through the rollformer. The male and female lock seams (“pittsburg”, “snap lock”, or other forms) are formed simultaneously in a single pass through operation while minimizing the floor space required for the present art apparatus.
The present art apparatus comprises a laterally moving rollforming head assembly having two or more distinct sets of outboard tooling or rollers mounted upon opposed spindles. In a preferred embodiment, the female lock seam is formed on a leading edge of a coil or sheet metal strip and the male lock seam is formed on the trailing edge of the pre-shear duct section as the head moves across the section. Alternative embodiments may reverse the female and male lock seam positioning on the leading and trailing edges.
The present art apparatus allows sheet material fed from a coil cradle to pass through a beader, notcher, and/or shear as necessary. The sheared sheets then proceed through the present art pass through inline seam rollformer where a pittsburgh, snap lock, or other type of seam is formed. Thereafter an edge flange rollformer is often utilized to flange the notched edge of the duct. If the duct requires insulation, a glue and insulation is applied and/or pinned to the sheared sheet. An automatic brake finishes the sheared sheets by forming them into an “L” or full wrapper shape. Unique to the present art, all of the aforesaid is completed inline without a 90 degree transfer of any of the sheet material.
Accordingly, it is an object of the present invention to provide an inline pass through seam rollformer which utilizes a minimum of space yet is capable of forming male and/or female lock seams in a single pass without an unnecessary lateral or horizontal movement of the sheet material.
Another object of the present invention is to provide an inline pass through seam rollformer which is capable of simultaneously forming said lock seams in a single pass.
A further object of the present invention is to provide an inline pass through seam rollformer which is which is capable of utilization with a fully or semi automatic duct forming line whereby “L” shaped or full wrapper duct sections may be formed and finished.